[Neos] Problems with Creating a TYPO3 Neos plugin

[Patric Eckhart]

Hey,

I followed the following steps: (Creating a TYPO3 Neos plugin) 
http://docs.typo3.org/neos/TYPO3NeosDocumentation/IntegratorGuide/CreatingAPlugin.html

When I placed the Plugin to my site I get this error:
Exception while rendering
page<TYPO3.Neos:Page>/
body<TYPO3.TypoScript:Template>/
content/
main<TYPO3.Neos:PrimaryContent>/
default<TYPO3.TypoScript:Matcher>/
element<TYPO3.Neos:ContentCollection>/
itemRenderer<TYPO3.Neos:ContentCase>/
default<TYPO3.TypoScript:Matcher>:
The TypoScript object at path "page/body/content/main/default/element/itemRenderer/default/element" could not be rendered: Missing implementation class name for "MyComp.Guestbook". Add @class in your TypoScript configuration. (20150222134909e40a37)

Can you help me?